<template>
  <div class="detail-header">
    <router-link 
    tag="div" 
    to="/home"  
    class="header-abs"
    v-show="showAbs"
    >
      <i class="iconfont header-abs-back">&#xe624;</i>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link class="header-fixed-link" to="/home"  >
        <i class="iconfont header-fixed-back">&#xe624;</i>
        景点详情
      </router-link>
    </div>
  </div>
</template>

<script>
  export default {
    name:"DetailHeader",
    data(){
      return{
        showAbs:true,
        opacityStyle:{
          opacity:0
        }
      }
    },
    methods: {
      handleScroll() {
        let top= document.documentElement.scrollTop
        if(top > 60 ){
          let opacity=top/140
          opacity=opacity>1?1:opacity
          this.opacityStyle={opacity}
          this.showAbs=false
        }else{
          this.showAbs=true
        }
      }
    },
    activated(){
      window.addEventListener('scroll',this.handleScroll)
    },
    deactivated(){
      window.removeEventListener('scroll',this.handleScroll)
    }
  }
</script>

<style lang="stylus" scoped>
@import '~css/mixins.styl'
  .header-abs
    position absolute
    top .2rem
    left .2rem
    width .8rem 
    height .8rem
    line-height .8rem
    border-radius .4rem
    text-align center
    background-color rgba(0,0,0,.8)
    .header-abs-back
      color #fff
      font-size .4rem 
  .header-fixed
    z-index 2
    position fixed
    top 0
    left 0
    right 0
    height $HeaderHeight
    line-height $HeaderHeight
    text-align center
    color #fff
    background-color $bgColor
    font-size .32rem
    .header-fixed-link
      color #fff
    .header-fixed-back
      position absolute
      top 0
      left 0
      width .64rem
      text-align center
      font-size .4rem 
      color #fff
</style>